How do children search for seen and remembered people and objects, when the search takes place in a large-scale spatial environment? The proposed research addresses this question with children of preschool and elementary school ages. It differs from earlier research in spatial cognitive development in that it (a) takes place in large-scale spaces rather than employing small-scale models and (b) examines children's knowledge of strategic search procedures rather than their purely featural representations of space. Because of the paucity of research on this question data from two preliminary studies is presented to provide a conceptual and empirical basis for the nine proposed experiments. These nine experiments are to be carried out over three years, using subject populations in Tempe, Arizona and in Ann Arbor, Michigan. They address a number of important issues, hiterto unexplored, in the child's developing memory for, and search skills within, large-scale spatial envirnoments. Experiments 1, 2, 3, 4, 5, and 6 follow up important developmental issues raised by the preliminary research. They will provide data on th relevant skills in memory, strategic searching, and in the logical processing of ordered information. Experiment 7 investigates the development of search skills in very young children using natural tasks in their everyday child-care environments. Experiments 8 and 9 are a proposed beginning to the study of children's spatial knowledge of their own homes. They incorporate techniques for studying both the strategic acquistion of knowledge about a new home environment and the ability to use this knowledge to locate, store, and retrieve objects in the home.